Dr. Julian Bashir implanted Bareil Antos with a positronic matrix to keep him alive after part of his brain stopped functioning due to a bad reaction to various medical treatments Bashir had been forced to perform to keep Bariel available to assist in crucial negotiations with the Cardassians. Bareil awoke but said that the sensations he was experiencing did not seem real and seemed like a distant memory. Later, when other parts of Bareil's brain stopped functioning, Bashir chose to let Bareil die rather than replace the rest of his brain with positronic implants, feeling that he wouldn't be himself if any more of his brain was replaced. (DS9: "Life Support")

It is not mentioned whether or not this technology is the same technology used in Data's brain.